get_directory_as_zip method is not raising an error for false or missing credentials

[Micromegass]

When using the method get_directory_as_zip and valid credentials to access the cloud are not provided or the credentials are wrong the method goes ahead and saves a corrupt zip-file. Or rather a zip file without content but it still returns the boolean value True.

This results in a misleading error messages for further code. For instance, if a method to unzip the file after the download is being written, a BadZipFile error is raised misplacing the location of the error.

My suggestion would be to catch this error in the get_directory_as_zip method and not return the boolean True for this case. In general, I think it would be better to not return a boolean but rather the status code so it is more flexible. Another option would be to solve this directly in the login method.